A voice response service apparatus interacting with users through voice responses. An attribute storage stores an age of each user. A voice volume controller sets a volume level of a voice response for a user to a level corresponding to the user's age, as stored in the attribute storage. A voice synthesizer synthesizes voices for the voice responses at the volume level set by the voice volume controller. A sex of the user can also be stored and used by a tone controller to select a tone of the voice responses for the user from among a male voice and a female voice based on the user's sex. The voice synthesizer then synthesizes voices with the tone selected by the tone controller.